CVE-2026-84115: Privilege Escalation (CVSS 8.3)

Description

A vulnerability was found in Cleo Harmony up to 5.8.1.10. The affected element is an unknown function of the file /api/connections of the component JWT Refresh Token Handler. Performing a manipulation of the argument Bearer results in improper privilege management. The attack is possible to be carried out remotely. The exploit has been made public and could be used. Upgrading to version 5.8.1.11 is sufficient to fix this issue. It is recommended to upgrade the affected component.

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CVSS v3.1 Score

8.3

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L

EPSS — Exploit Prediction

0.0028

Probability of exploitation

0.21%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-266 CWE-266

CWE-269 CWE-269

References

Other References

https://support.cleo.com/hc/en-us/articles/30258468834583-Cleo-Harmony-5-8-1-Release-Notes#Version58111 https://vuldb.com/cve/CVE-2026-84115 https://vuldb.com/submit/882468 https://vuldb.com/vuln/397558 https://vuldb.com/vuln/397558/cti https://vuldb.com/submit/882468

Frequently Asked Questions

What is CVE-2026-84115? +

A vulnerability was found in Cleo Harmony up to 5.8.1.10. The affected element is an unknown function of the file /api/connections of the component JWT Refresh Token Handler. Performing a manipulation of the argument Bearer results in improper privilege management. The attack is possible to be carried out remotely. The exploit has been made public and could be used. Upgrading to version 5.8.1.11 is sufficient to fix this issue. It is recommended to upgrade the affected component. It has a CVSS v3.1 base score of 8.3 (HIGH).

How severe is CVE-2026-84115? +

CVE-2026-84115 has a CVSS v3.1 score of 8.3 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0028, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-84115? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-84115